I typically don't like to publicly shame a company on a forum for bugs, but this bug is critical IMO and I reported over a year ago (as in submitted bug report ticket #272855). If you do a file integrity hash value check, FDM computes the hash and displays it. The letters A through F, if any in the hex number are all lower case. If you enter a hash value to compare against using CAPITAL letters, the file integrity will fail with the message 'Verification Failed', giving the user the impression that the download is no good. If you enter the hash value using lower case letters, the comparison returns valid (obviously, the hash value you enter must be correct, capitial or lower case). IMO, this is a critical bug, because a user may try to re-download a file over and over and over, thinking he has a corrupted file, when in fact the file is fine. And honestly, for a file download program, getting hash value comparison is pretty essential, if you're going to even offer that functionality , it has to be right. For a real large file (think Apple OS updater), this is a lot of wasted time and bandwidth. And all because of simple error between using Capital vs lower case letters.
The bug is so obvious; the program is comparing what the user enters directly to the hash value it calculated, as a string comparison. ONE line of code in the C language will perform a case conversion on a string; problem solved. Disappointing, otherwise, great download manager.